Coal cutting bit and holder therefor



March 19, 1946. 1 EL. FULK COAL CUTTING BIT AND HOLDER THEREFOR Filed Jan. 27, 1943 Patented Mar. 19, 1946 COAL CUTTING BIT AND HOLDER THEREFOR Frank L. Falke, Terre Haute, Ind.,.assignor to Frank Prox Company, Inc., Terre Haute, Ind.,

a corporation of Indiana Application January 27, 1943, Serial No. 474,044

2 Claims. (Cl.v mi2-33) The present invention is a continuation in part of my application Serial No. 385,972, filed March 31, 1941.

A primary object of the present invention is to provide for the optional use of a multi-pointed factory hardened bit in a cutter chain adapted also for the use of conventional one-half inch by one inch shanked mine bits; so as to permit the user to employ either the conventional mine bit or my factory bit at will. A further object is to provide a plural-use bit made of a small piece ofsteel so formed as to carry out the intentions and attain the objectives of the present invention. A further object is to provide a positive and inexpensive keeper through which to associate my bit with a chain block formed with a socket adapted also to hold ordinary mine bits. A further object of the invention is to provide an assembly in which a one-piece holder or keeper element is associated with a plural-pointed bit to support the latter upon a mining machine chain link With a portion of the 'bit and a portion of the holder received Within a socket formed in the link, with the keeper positioned Wholly laterally on one side of the bit relative to the cutting path of the bit, so that the bit directly engages, and is laterally supported in one direction by, one lateral wall of the link socket, While the bit directly engages, and is laterally supported in the opposite direction by, the holder which, in turn, directly engages, and is laterally supported in said last-mentioned direction by, the opposite lateral wall of said link socket. A further object of the invention is to provide, in an organization of the character under consideration, alternatively usable bits and holders of variably complementary thicknesses, so that, for instance, the operator may at one time use bits 1/8 thick with holders having a complementary thickness of and may at another time use bits 3A, thick with holders having a complementary thickness of 1/8", the novel association of the bit and the holder disclosed herein being effective to support even so thin a holder against breakage under lateral stresses encountered in machine coal cutting. A further object of the invention is to provide, for use in holding a plural-pointed bit in a socketed mining machine chain link, a holder or keeper formed to engage one lateral surface of such bit and to engage certain of the edges of said bit at a plurality of points and in such relative positions as to hold said bit against movement with respect to the holder in the plane Qf the bit and in the direction of the active point thereof, While leaving the opposite lateral surface of said bit open to engagement with a lateral wall of the link socket, said holder, together with said bit, being insertable in said link socket, so that the bit is laterally supported between a lateral Wall of the link socket and a surface of the holder, while the bit directly engages said link socket wall and the holder, and the holder di illustrated and described, so long as the scope of the appended claims is not violated.

In the drawing,

Fig. 1 is a side view of a bit and keeper constructed in accordance with my invention and assembled in the standard socket of a standard chain block, vparts being shown in section for clarity of illustration;

Fig. 2 is 'a view taken substantially on the line 2-2 of Fig. 1 and looking in the direction of the arrows;

Fig. 3 is a similar view showing a further form of keeper;

Fig. 4' is a similar view showing still another type of keeper; and

Fig. 5 is a plan view of a modified link carrying still another form of bit and keeper assembly constructed in accordance with my invention, parts being shown in section for clarity of illustration.

The problem of so constructing a factory bity 'and holder as to be received in a conventional mine bit socket having rectangular dimensions slightly greater than one-half inch by one inch, so as to permit the optional alternative use of either the factory bit or a standard mine bit is very complicated, and 'numerous attempts to solve that problem have failed of success. A principal difficulty is that of providing sulicient strength in the factory bit and holder to avoid breakage of either, while holding the dimensions thereof small enough tot the relatively small block socket. It must be remembered that in cutting coal, hard impurities are often met which may either break or rapidly abrade away any parts of bits and' holders projecting outwardly beyond the link, 'and may even ruin the link itself. The active 'point of thev bit must be a considerable there is no socket portion corresponding to the socket portion 49', since the position of the keeper 513 axially of the socket Il) is depended upon to hold the bit edge 53 in engagement with the edge 65 of the mouth of the socket l0.

Referring, again, to the details illustrated in Figs. 1 and 2 (many of which will be incorporated in the modied forms of my invention illustrated in Figs. 3 to 5) it will be seen that my keeper 36 extends outwardly beyond the link socket, so that keeper surface 31 provides an upwardly extended lateral support for my bit, and in order to provide a similar extended support at the opposite side of my bit, I provide an extension of socket wall 9 beyond the link by welding alongside that wall a block 2l, whose face 22 provides an extension of the wall 9 beyond the socket mouth alongside my bit 30.

, The surfaces 44 and 41 converge toward the active bit point 3l, wherefore, as will be obvious, the bit is held against any movement when the bit-and-keeper assembly is secured in place in the socket l0. The keeper 36 is held against movement in the socket by engagement of the nose of the screw Il in one or the other of the indentations 49 or 49' on the leading edge of the keeper. Normally, the indentation 49 is used, but `if a squeeze condition arises, the kerf may be widened by shifting the bit-and-keeper assembly and engaging the screw H in indentation 49.

Ln further consideration of the limitations imposed, and the governing dimensions, it will readily be apparent that in devising my improved bit and keeper I have contrived to satisfy all the exacting requirements involved. My bit 30 is of a length to project one and a half inches outwardly beyond the block socket, and to present a suicient depth of engagement of its side surface 4i within the socket Ill against socket Wall 9, the length of my bit being more than twice its maximum width. Obviously, with av substantial portion of my bit received Within the socket, I must provide that the body width of the received portion of the bit be substantially less than the width of a side wall of the socket l0, which is slightly more than one inch to accommodate stand-ard mine bits.

Obviously, also, in order to interpose my bit between the wall 9 ofthe socket and the keeper surface 3l,y my bit thickness must be very substantially less than approximately one-half inch which is the width of the socket.

Those familiar with the art will recognize the prime desirability of my employment of keeper 36 interposed between my bit and the socket wall I5. My bit is meshed with the keeper, by which I mean that it is supported with one lateral surface based upon a lateral surface of the keeper and with a plurality of its edges engaged by means on said keeper and cooperating with such bit edges, whereby the bit is held against movement with respect to the keeper. Thus, the bit is meshed with the keeper, while the keeper is held against movement in the socket by screw Il engaging in one or the other of the indentations 49 and 49 in the keeper. Yet I can very rapidly unlock the keeper, reverse or replace the bit, and positively relock the assembly, only a partial turn of the screw I i being required. I could not achieve these advantages if I attempted to supportv my bit without the keeper interposed at the side of the bit, or without the screw engaging the keeper. If I attempted to socket my keeper to place` my bit into a central opening therethrough, the'satisfactory form-ation of such a socket would CFI be extremely difficult if not impossible, and such a' socket would load up with coal 'dust which would seriously interfere with the setting of bits, or the socket Walls might mash in under abrasion to interfere with changing the bit.-

`If, instead of the single, simply formed, and rugged keeper I have devised, I should try to employ twometal clamps to associate my bit with the block socket, these clamps would necessarily be so thin and Weak (in view of the space limitations imposed by the standard socket) as to be unreliable. Furthermore, it is highly desirable to use as few loose parts as possible.

The block 2l, welded at the side of the bit socket in block l, obviously will not interfere with the use of ordinary one-half inch by one inch shanked standard mine bits, when desired. The block 2| and the outwardly extended portion of the keeper 36 have their extremities disposed at least one inch from the active cutting point of my bit, so that there is little possibility of injury to these elements from coring, or in case a substantial portion of the extended end of the bit is abr-aded away rapidly against rock.

The abutmentsupstanding from the surface 3l of my keeper are of substantially less dimensions than the thickness of my bit, as is clear from a consideration of Fig. 2. This arrangement is desirable in order to prevent dirt accumulation, yand `a very slight projection of these abutments is suiiicient, in coordination with the socket walls, to retain the bit in operative position.

It will also be apparent that I may, with the simple construction provided, accomplish the extremely desirable objective of permitting theuser a choice of several sizes of factory bits to perform the operations desired and indicated by the users particular cutting conditions. The bit illustrated, with its relatively thin body and slender piercing point is ideal for easy cutting where minimum coal disintegration is desired. If the user has hard impurities to out, bits with heavier body sections and heavier duty cutting points could be supplied, the use of such bits requiring merely an interchange of the keepers 36, thicker bits requiring thinner keepers.

Under the trying limitation of space imposed, it will be seen that I do not rely, as often attempted heretofore, upon the strength of a bit holder, but rather upon the strength of my bit itself and the strength of the side walls of the bit block socket to which I directly transmit the stresses encountered in cutting, it being obviously impossible to break my simple keeper at any point by shocks from any direction, since the forces acting upon it are almost entirely compressive. The advantages inherent in the use of a small, plural-pointed, replaceable bit, together with a one-piece shanked holder so constructed that the bit lmay be meshed with one lateral surface of the holder before introducing the assembled bit and holder into .the standard socket of a mining machine chain link in such a relation that one lateral surface of the bit is pressed, by the holder, into engagement with a correspondingly surfaced lateral wall of that socket, while the lateral surface of the holder opposite that surface with which the bit is meshed, is pressed against the opposite lateral wall of the link socket, so that lateral stresses applied to the active point of the bit in one direction are directly resisted by the solid wall of the link, while such stresses impressed in the opposite direction are transmitted purely compressively through the holder to the oppositesideLof the link, arerso important that they iquite overbalan'ce any .apparent `disadvantage in the locationof the .cutting pointin aposition oiset from Lthemedian `plane of the link. It has for so long vbeen considered necessary, the mining machine chain .art,to locate the vcut-- ting point midway between` parallel planes rcontaining respectively .thelateral .boundaries of the holder, .that the thought oipermitting the cutting .point .to lie outside that iplane is 1 quite startling, Butl .have .found ithat .assembliesasuch .as those illustrated Vherein operate r quite rsatisfactorily, and that the-advantages tinherentin the concept abovedescribed completely outweigh any disadvantages varising .from the yunconventional relationship between the cuttingpoint and `the link.

L1 `this connection, it is tobe .noted that "the lateral dimension ofthe link socket .is standardly one .half iinch. Any Vbit .in standard use 'has a cutting point which vwill produce akerf at least one-eighth inch wide. Therefore, .a bit of the character illustrated herein and .mounted 'as shown, and having a 'thickness of ras" or more willcut atleast partially'in the. SameY path which would be cut by a bit standardly mounted,

A :still .further .simplification of 4structure is illustrated inFig. 4, in which a-.bit '10, .having a lateral contour Vsimilar to :the contours ofthe bits and;5,.is formed-'toprovidecutting points 7l and 12 at the intersections, with a .leading cutting edge 13, of trailing edges T4 and 1.5 meeting said cutting edge in substantially equal angles. A keeper f1.6 is formed to provide a khat surface or floor 'Hfagainst whichis engaged and supported one lateral-surface of tthe bit-10. The keeper head lll is .provided with a substantially erpendicularlyV projecting .flange 'I9 extending laterally from the surface TI and formedto provide a surface 89 substantially .perpendicular-to said surface 11, 'Acylindri'cal post l projects in `the same direction #from the surface 11. It will be seen that the'surface 80 is adapted to be engaged by,fand to support, thattrailing edge of the I bit which :intersects the i leading .edgeto form the currently active cuttingpoint. .'It will :further be seen that the planeftangent tothe cylindrical surface of the post'l at the point of engagement thereof by thezbit Yedge '13'touches the leading edgei83 ofthe :mouth of the llink socket lil and converges with the surfacevil toward the currently 'active :cutting point, It will further be .seen that 'thetraillng edge of the "bit 'intersecting the leading-edge thereof ,in the currently inactive cutting point is, `When the holder and bit assembly is set in the rsocket I0, engaged'and Supportedby the trailing edge-s2 of themoutn of the socket l0, The above-mentioned plane is susbtantially the plane ofthesurface d'4 of Fig. 1, and, with'the surfaceiS, outlines that .portion of the iioor T1 with Whichthebitis engaged.

The leading :edge of the hlder'is formedwith a'socket134 similar tofthe socket'in'which'the nose of the screw il maybe engaged `to hold the holder-and-bit assembly lin the illustrated 'position, in which the bit is solidly 'secured inplace. In Fig-5,1 have 'illustratedan organization incorporating manyA of the advantages 'of Vthe structures yillustrated iin Figs. 1 tori. In that figure, I .have shown a chainlinkil in which is formed, bydrilling'or thelike, acylindrical socket 9|. After the socketgi :hasfbeenformed apartcylindrical block 92 isset .thereinto ian'd Welded in '..place, said block .being formed `.to provide .a plane surface .93 so located -as -to Vconstitute 'a minor arc ofztheperiphery of the-.socketSL .A keeper 94, which is part-cylindrical. in 'cross section,and which is formedto provide a-surface substantially parallel with the surface 93, -is iurther forrned in that surface With an indentation contoured to correspond with the elevational contour of a portion of a bit 96. The bit `96 may fhave any elevational Acontour which provides fora plurality of alternatively usablecutting points ,and which further provides, in any selectiveposition of the bit to bring any .one of the 'cutting points into active position, for contour surface portions which converge toward the currently active cutting point, whereby therengagement of the'bit in the indentation 95', with one lateral surface pressed against the oor of said indentation, rmly holds the bit against movement with respect to the holder94.

.Thebit holder 9d is formed with a leading surface-91 for engagement by the nose of a set screw 99 .to :hold the assembly in place in the socket Bl. Saidsurface Sl may or may not be the bottom of asingle or double socket like the socket 66 or the sockets 4S, '49. Y

vI claim as my invention:

il. Ina mining machine chain, a link having a socket, a bit Whose elevation comprises two sides converging at equal angles with a third side to form two cutting ends, a bit keeper having a shankand a head, said shank being enterable in said :link socket and having front and rear surfaces and one lateral surface engaging correspending walls of said socket when so entered, said'keeper-being formed to provide a iat floor opposite said one lateral surface, said floor being spaced from the corresponding wall of ksaid socket, means projecting substantially perpendicularly from said floor to Vprovide abutments angularly related'to each other at an angle equal to `the `angle included between said two 'firstmentioned sides oi said'bit, and other meansr projecting lsubstantially perpendicularly 'from said floor, said bit being supported with one lateral surface 'pressed against said floor, 'the opposite lateral surface pressed against said 'last-mentionedsocket wall, its two inst-mentioned sides engaged with said nist-named means, and its third side engaging said last-named'means and anedge of the mouth of said socket, and means for retaining said keeper shank against removal from said socket.

2. In a mining machine chain, a vlink "formed with'an-outwardly opening socket of rectangular cross section whose dimension in the direction offchain travel is approximately lino-h and .Whose dimension transverse to the direction of chain travel is'approxima'tely 1/2 inch, a bit keeper havingfa head .and having a shank of rectangular cross section, said shank being enterable in said socket, the cross sectional dimension of said shank in ithe direction of chain travel being slightlyllessthan 1 inch and the cross sectional dimension ofsaid shank transverse to the direction of chain travel'being less than 1/inch,said

.keeper rbeing `formed to provide a plane iloor parallel with the plane of chain travel and parallel `with one `lateral Wall of said shank andwith alatera'lwall or said socket engaged by said lateral shank wall, a bit of rectangular cross section, the v'distance between `said shank 'wall and said iloorplus the thickness of said bit being substantially Yequal .to the minor dimension of said socket ".whereby, when said vbit is rlaid with .one lateral .surface engaged with said door and said bit'andfkeeper shank are inserted in saidsocket,

said lateral Wall of said shank engages one lateral Wall of said socket, one lateral Wall of said bit engages said floor, and the opposite lateral wall of said bit engages the opposite lateral wall of said socket, said bit having a lateral elevation comprising two sides converging at equal angles with a third side to form two cutting ends, means projecting substantially perpendicularly from said keeper floor toward, but not to, said lateral Wall of said socket engaged by said bit, and providing abutments engaging said three sides of said bit to hold the latter, when said bit and shank are entered in said socket, against movement relative to said keeper, and means for retaining said keeper shank against removal from said socket.

FRANK L. FULKE. 

